SAN FRANCISCO -- Zynga shareholders are cashing out their chips as lady luck appears destined for Atlantic City.

Shares of Zynga today slid 3% as the prospects of real money online gambling in the U.S. moved closer to reality for its brick-and-mortar casino rivals. Zynga is making a bid for gambling in the U.K. and the U.S., but New Jersey's Atlantic City may get there faster.

A New Jersey bill that would allow online gambling on casino games in Atlantic City was approved by the state's Senate on Thursday. The bill would permit state residents to gamble over the Internet with licensed casino operators or their Internet gambling partners.

"If New Jersey's casinos wish to compete in the 21st century, we have to give them the freedom to adapt to a 21st Century marketplace," said Senator Raymond Lesniak, D-Union, in a statement.

Zynga shares lost 9 cents at $2.30 in midday trading.

Zynga has filed an application for a license with the Nevada Gaming Control Board, a process that could take up to 18 months. The social games giant is also seeking a stake of virtual casino dollars in the U.K., under a deal with Bwin.Party Digital Entertainment that would bring real money poker and casino games, starting in 2013.

Zynga operates a wildy popular online poker game. Its Texas HoldEm Poker doesn't permit, and can't under current laws, real money gambling. The game boasts 6.7 million daily active users, according to AppData.

Yet Zynga's path toward real-money gambling remains an uncertain jackpot. The games giant is going to spend years trying to get a share of the highly competitive market, says industry consultant Tadhg Kelly. "There are hundreds of players that know the industry backwards."